1. Technical Field
The present invention relates to a power supply device, and more particularly, to a power supply device which includes a protection circuit for protecting the power supply device from excessive current.
2. Description of the Related Art
With the increase of an information society, importance of display apparatuses has increased as a visual information transmission medium, and the display apparatus should meet requirements such as low-power consumption, quantification, high-quality, and the like so as to play an important position in the future.
The display apparatus may include a driving unit for applying a pulse to a plurality of electrodes, and a power supply device of the display apparatus supplies an electric power to drive the driving unit. In this instance, as the power supply device of the display apparatus, an SMPS (Switching Mode Power Supply), and the like may be used.
Here, the SMPS may be a device that converts a DC voltage into a sinusoidal voltage using a switch element such as an MOSFET (metal-oxide-semiconductor field effect transistor), and then outputs a DC voltage of a desired level using a converter.
Meanwhile, damages to the display apparatus frequently occur in a manner such that excessive current is quickly applied to the display apparatus due to several external factors. In order to protect the display apparatus from excessive current, the power supply device may include a protection circuit that determines whether the excessive current is applied, and performs a protection operation such as stopping the driving of the power supply device when the excessive current is determined as being applied.
The power supply device in the related art includes a sensing resistor that senses a current flowing in an inductor or a transformer, a protection circuit that performs a protection operation when a voltage sensed in the sensing resistor is equal to or larger than a reference voltage (Vref), and a driving circuit that cuts off an electric power applied to a gate of the switch element by the protection operation of the protection circuit.
FIG. 1 is a diagram for explaining a protection operation of a power supply device according to the related art. In FIG. 1, a voltage sensed by a sensing resistor, presence/absence of a protection operation of a protection circuit, and a gate voltage of a switch element output from a driving circuit are sequentially shown.
Referring to FIG. 1, the power supply device according to the related art has a problem in that the protection operation is performed even though noise of singularity such as an A-waveform other than the excessive current is applied.
As a result, the protection circuit may malfunction due to the noise.
Accordingly, in the related art, there is a demand for dividing excessive current and noise to prevent malfunction of the protection circuit due to the noise.